optimize a query in MySQL 5.7

Here is my system:

Linux Ubuntu 18.04 LTS
MySQL 5.7

I have a query (below) that is taking too long to complete.

It is taking as long at 9 seconds to complete. That is an untenable amount of time for a user when waiting for a web page to complete loading.

Also, the dataset is large and growing. The events table has 250,000 rows. I tend to add 1200 to 1800 rows per day.

To help in optimization, I would like to add indexes and such, but am stumped about how (and if) I can do that with the derived/joined select query I have.

Here is my query. (Anyone know how to limit the width of the output so that we don't have to scroll to the right to see the full line?)

mysql> explain select OUTSIDE.ownerUID as Owner, 
  OUTSIDE.propUID as Property, 
  OUTSIDE.camname as 'Camera Name', 
  OUTSIDE.direction as Direction, 
  OUTSIDE.camtimestamp as 'Event Time', 
  convert_tz(now(),'UTC','US/Central') as Now, 
  sec_to_time(convert_tz(now(),'UTC','US/Central') - OUTSIDE.CamTimeStamp) as 'Elapsed Time' 
from events OUTSIDE, 
  (select camname,max(camtimestamp) as maxtimestamp from events group by camname) as INSIDE 
where OUTSIDE.camname = INSIDE.camname 
  AND OUTSIDE.camtimestamp = INSIDE.maxtimestamp;
+----+-------------+------------+------------+-------+----------------------+--------------+---------+---------------------+--------+----------+-------------+
| id | select_type | table      | partitions | type  | possible_keys        | key          | key_len | ref                 | rows   | filtered | Extra       |
+----+-------------+------------+------------+-------+----------------------+--------------+---------+---------------------+--------+----------+-------------+
|  1 | PRIMARY     | <derived2> | NULL       | ALL   | NULL                 | NULL         | NULL    | NULL                | 263103 |   100.00 | Using where |
|  1 | PRIMARY     | OUTSIDE    | NULL       | ref   | camtimestamp,camname | camtimestamp | 6       | INSIDE.maxtimestamp |      1 |    99.73 | Using where |
|  2 | DERIVED     | events     | NULL       | index | camname              | camname      | 257     | NULL                | 263103 |   100.00 | NULL        |
+----+-------------+------------+------------+-------+----------------------+--------------+---------+---------------------+--------+----------+-------------+
3 rows in set, 1 warning (0.03 sec)

Here are the results of the query:

mysql> select OUTSIDE.ownerUID as Owner, 
  OUTSIDE.propUID as Property, 
  OUTSIDE.camname as 'Camera Name', 
  OUTSIDE.direction as Direction, 
  OUTSIDE.camtimestamp as 'Event Time', 
  convert_tz(now(),'UTC','US/Central') as Now, 
  sec_to_time(convert_tz(now(),'UTC','US/Central') - OUTSIDE.CamTimeStamp) as 'Elapsed Time' 
from events OUTSIDE, 
  (select camname,max(camtimestamp) as maxtimestamp from events group by camname) as INSIDE 
where OUTSIDE.camname = INSIDE.camname 
  AND OUTSIDE.camtimestamp = INSIDE.maxtimestamp;
+-------+----------+-------------+-----------+---------------------+---------------------+--------------+
| Owner | Property | Camera Name | Direction | Event Time          | Now                 | Elapsed Time |
+-------+----------+-------------+-----------+---------------------+---------------------+--------------+
|     1 |        1 | wls1        | In        | 2020-01-30 12:27:31 | 2020-01-30 12:29:53 | 00:03:42     |
|     1 |        1 | wls2        | Out       | 2020-01-30 12:25:29 | 2020-01-30 12:29:53 | 00:07:04     |
+-------+----------+-------------+-----------+---------------------+---------------------+--------------+
2 rows in set (6.49 sec)

========================================================== Thank you to all who answered the question or commented. I took Uueerdo's suggestion of a composite index and came up with the following results:

mysql> create index CamNameCamTime on events (camname,camtimestamp);

mysql> select OUTSIDE.ownerUID as Owner,
           OUTSIDE.propUID as Property,
           OUTSIDE.camname as 'Camera Name',
           OUTSIDE.direction as Direction,
           OUTSIDE.camtimestamp as 'Event Time',
           convert_tz(now(),'UTC','US/Central') as Now,
           sec_to_time(convert_tz(now(),'UTC','US/Central') - OUTSIDE.CamTimeStamp) as 'Elapsed Time' 
      from events OUTSIDE,
         (select camname,max(camtimestamp) as maxtimestamp 
           from events group by camname) as INSIDE
      where OUTSIDE.camname = INSIDE.camname AND OUTSIDE.camtimestamp = INSIDE.maxtimestamp;
+-------+----------+-------------+-----------+---------------------+---------------------+--------------+
| Owner | Property | Camera Name | Direction | Event Time          | Now                 | Elapsed Time |
+-------+----------+-------------+-----------+---------------------+---------------------+--------------+
|     1 |        1 | wls1        | In        | 2020-01-30 18:43:19 | 2020-01-30 18:44:33 | 00:01:54     |
|     1 |        1 | wls2        | Out       | 2020-01-30 18:41:51 | 2020-01-30 18:44:33 | 00:04:42     |
+-------+----------+-------------+-----------+---------------------+---------------------+--------------+
2 rows in set (0.00 sec)

mysql> explain select OUTSIDE.ownerUID as Owner,
    ->            OUTSIDE.propUID as Property,
    ->            OUTSIDE.camname as 'Camera Name',
    ->            OUTSIDE.direction as Direction,
    ->            OUTSIDE.camtimestamp as 'Event Time',
    ->            convert_tz(now(),'UTC','US/Central') as Now,
    ->            sec_to_time(convert_tz(now(),'UTC','US/Central') - OUTSIDE.CamTimeStamp) as 'Elapsed Time'
    ->       from events OUTSIDE,
    ->          (select camname,max(camtimestamp) as maxtimestamp
    ->            from events group by camname) as INSIDE
    ->       where OUTSIDE.camname = INSIDE.camname AND OUTSIDE.camtimestamp = INSIDE.maxtimestamp;
+----+-------------+------------+------------+-------+-------------------------------------+----------------+---------+------------------------------------+------+----------+--------------------------+
| id | select_type | table      | partitions | type  | possible_keys                       | key            | key_len | ref                                | rows | filtered | Extra                    |
+----+-------------+------------+------------+-------+-------------------------------------+----------------+---------+------------------------------------+------+----------+--------------------------+
|  1 | PRIMARY     | <derived2> | NULL       | ALL   | NULL                                | NULL           | NULL    | NULL                               |    2 |   100.00 | Using where              |
|  1 | PRIMARY     | OUTSIDE    | NULL       | ref   | camtimestamp,camname,CamNameCamTime | CamNameCamTime | 263     | INSIDE.camname,INSIDE.maxtimestamp |    1 |   100.00 | NULL                     |
|  2 | DERIVED     | events     | NULL       | range | camname,CamNameCamTime              | CamNameCamTime | 257     | NULL                               |    2 |   100.00 | Using index for group-by |
+----+-------------+------------+------------+-------+-------------------------------------+----------------+---------+------------------------------------+------+----------+--------------------------+
3 rows in set, 1 warning (0.00 sec)

Success!