Now in ZBXNEXT-3086 we acquire unique conditions hash set. This helps to avoid same condition double checking per event.
However this can be improved even further by bulk selects if there are more than one event at a time.
After unique conditions are acquired it is possible to run through all unique conditions and do bulk select for all events instead of just one.

It is expected that after optimization the query count will be equal to conditions.
Before optimization query count is equal to condition * events.