Have a look at the On Overlap property of your scheduled event. You probably want this set as Skip Next to stop the same microflow from queuing multiple times, but it depends on your use case.

https://docs.mendix.com/refguide/scheduled-events/#long-events

If you want the microflow to only run a certain number of times, then you will need to implement this logic in the microflow itself. You can store the count in an entity that you can retrieve at the start and see if the count has reached your limit or not. Remember to increment this count at a suitable point in your microflow.

I hope this helps.