Use combine_first on two Series given by the two rows of you dataframe:

import pandas as pd
df = pd.DataFrame({'team_token':['abc', 'abc'], 'day1': [1, None], 'day2' : [None, 1]})

df.loc[0].combine_first(df.loc[1])

gives:

 team_token  day1    day2
0   abc           1       1 

EDIT:

A better solution that works also with your updated answer is simply:

df.max()

assuming that you day columns contain either Nan or ones.

In case you have different team_tokens:

   day1  day2  day3 team_token
0   1.0   NaN   NaN        abc
1   NaN   NaN   NaN        abc
2   1.0   1.0   NaN        abc
3   NaN   NaN   NaN        abc
4   1.0   NaN   1.0        ddd
5   1.0   NaN   1.0        ddd
6   NaN   NaN   1.0        ddd

you can group_by and still take the max of the group:

df.groupby('team_token').max().reset_index()

#  team_token  day1  day2  day3
#0        abc   1.0   1.0   NaN
#1        ddd   1.0   NaN   1.0