Runtime claim based authentication Session timeout not working

I have the Runtime configured to use Claim-based authentication, and works fine, the issue we are facing it's that for security requirements we must have the Runtime session for 15 minutes, I have dollowed some articles manipulating the session state and some other parameters in the web config file but, still not working. My claim issuer (Single Sign On provider) it's configured to keep the token  alive for 8 hours, and I'm assuming somehow the session in K2 Runtime App is taking that timming as well, I wonder if someone knows any setting, configuration or workaround to solve this issue.