I believe you already figured it out, but here it is for future reference (note that this is still in BETA and you need to contact your Customer Success Manager (CSM) for access).
Menu (top bar, the 9 dots) > Control Center > Entitlements
See also the Mendix documentation for Entitlements and cloud tokens: https://docs.mendix.com/control-center/entitlements/
The screen looks something like this (with total, used and available), and rows for "mutations"
Goto the environment and click details. There you can see which plan you have. You can view the resources of each plan here: https://docs.mendix.com/developerportal/deploy/mendix-cloud-deploy/#resource-pack
And if you have enough resources you can change your scaling to multiple instances but that has some disadvantages like unable to live debug.
Regards,
Ronald