Since you're not working with real data there is no way to know if the indexes will be helpful or not. If the actual data has a high skew, for instance, 99% of your event_types are 1 or 3, then the index will just use extra space and will unlikely improve performance.
And no, you can't say "that won't be the case" because, as you stated, you're not working with an actual database. Asking us to "ignore lack of information about the actual DBMS, indexing, etc" is asking a brain surgeon to ignore their patient's other, traumatic injuries.
Link to original question for others who may want to weigh in, suggest reading it first:
We need to close one of these threads, they're duplicates. I'll let you choose which one.