What is the minimum threshold for getting rewards?

The minimum threshold for receiving your reward is 50 USD.

Curators who have reached at least 50 USD (normally corresponding to 100 tasks completed via the Jukebox mission) will receive the related amount directly. 

If the curator fails to achieve the minimum threshold by the end of the month, Musixmatch will also consider these completed tasks (not rewarded) when the minimum threshold is reached (50$).