Invalidate Cache for REST api call

Hey there!
I’m using the most recent version of confluence server and developing a custom plugin macro.

I’m calling a REST endpoint of my own plugin, to get some configuration parameters - “http://…/config/”
The Configuration-Object is a Active Objects instance.
If I change the AO-Configuration-Object, via Admin-Form, the REST call still returns the old config object, due to caching.
This is a change that rarely happens, but changes should have an effect immediately.
Thus, solutions like setting cache expiry intervals, or changing a query parameter on a regular bases, do not seem like an elegant solution.

Is there a way to use the CacheManager to invalidate the cache of the REST-API call, by hand? - What would be the name of the cache and its cache-key?
Or is there some other solution?

Thanks for any kind of hint to a possible solution!