Hi Sofia and welcome to the forums!
Good questions.
Yes, it is possible to use Google Maps API keys for the map functionality. In fact, here is a guide that will walk you through the process of setting it up, step-by-step:
Creating a Google Maps API Key
The Events Calendar will not make a call to the Google Maps API anywhere, other than pages that include events. You may need to reach out to your theme developer for tips on how to prevent its calls to the API from firing on calendar-related pages, if it’s attempting to do so there. Otherwise, the event functionality may not work as expected.
Does this help answer your question? Please let me know!
Cheers!
Geoff