You can go straight to the CCS DB's with a SQL query.
Web API's are usually slow anyway... as long as your DBA's allow the direct SQL connection, that'd be my suggestion.
Just don't hit any of the CCS "Views" - they were -apparently- coded by people who don't know much about SQL and they are horrendously misconfigured. You'll get timeouts and whatnot.
If you need further help, I can assist. I know the CCS table structure quite well.