Gremling console queries to JanusGraph are randomly slow

I have a super easy gremlin query which I send to a IBM Cloud hosted JanusGraph with gremlin console. Strangely, the execution time is very fast sometimes and then again very slowly. What can that be? The property uid is of type string and could be an GUID but also something other.

gremlin> g.V().has('uid', 'f287342c-ff84-4102-8f18-f3aa759470a7').hasLabel('product').profile()
==>Traversal Metrics
Step                                                               Count  Traversers       Time (ms)    % Dur
=============================================================================================================
JanusGraphStep([],[uid.eq(f287342c-ff84-4102-8f...                     1           1        1107.212   100.00
    \_condition=(uid = f287342c-ff84-4102-8f18-f3aa759470a7 AND ~label = product)
    \_isFitted=false
    \_query=[]
    \_orders=[]
    \_isOrdered=true
  optimization                                                                                 0.014
  optimization                                                                                 0.055
  scan                                                                                         0.000
    \_condition=VERTEX
    \_query=[]
    \_fullscan=true
                                            >TOTAL                     -           -        1107.212        -
gremlin> g.V().has('uid', 'f287342c-ff84-4102-8f18-f3aa759470a7').hasLabel('product').profile()
==>Traversal Metrics
Step                                                               Count  Traversers       Time (ms)    % Dur
=============================================================================================================
JanusGraphStep([],[uid.eq(f287342c-ff84-4102-8f...                     1           1         129.861   100.00
    \_condition=(uid = f287342c-ff84-4102-8f18-f3aa759470a7 AND ~label = product)
    \_isFitted=false
    \_query=[]
    \_orders=[]
    \_isOrdered=true
  optimization                                                                                 0.014
  optimization                                                                                 0.056
  scan                                                                                         0.000
    \_condition=VERTEX
    \_query=[]
    \_fullscan=true
                                            >TOTAL                     -           -         129.861        -
gremlin> g.V().has('uid', 'f287342c-ff84-4102-8f18-f3aa759470a7').hasLabel('product').profile()
==>Traversal Metrics
Step                                                               Count  Traversers       Time (ms)    % Dur
=============================================================================================================
JanusGraphStep([],[uid.eq(f287342c-ff84-4102-8f...                     1           1        2581.514   100.00
    \_condition=(uid = f287342c-ff84-4102-8f18-f3aa759470a7 AND ~label = product)
    \_isFitted=false
    \_query=[]
    \_orders=[]
    \_isOrdered=true
  optimization                                                                                 0.024
  optimization                                                                                 0.094
  scan                                                                                         0.000
    \_condition=VERTEX
    \_query=[]
    \_fullscan=true
                                            >TOTAL                     -           -        2581.514