You can always look up EPSG definitions at the EPSG registry online:
http://www.epsg-registry.org/https://epsg.org/
There you will find that units of that CRS are metres.
From this question
Can someone recognize the CRS?
I assume you have a custom CRS for it. In the definition string you can find an entry +units=m
which should answer your question.
Your grid should come up with 10 km spacing with the configuration from the screenshot.
If you are in doubt about distances you measured, there might be something else going wrong in your layer configuration.