The base ASA sees SSL flows as just TCP connections. The 5525-X is rate for 20,000 new connections per second and 500,000 total active sessions, so you are fine there.
The FirePOWER module similarly sees just TCP connections (unless you are trying to decrypt SSL - generally not done on this platform as it is in software and presents several challenges).
If you have further doubt, your partner reseller or Cisco SE can work with Cisco to use an internal tool and run your numbers to tell you the expected load on your firewall considering all factors holistically.