SQL queries break our game! (Back-end server is at capacity)
What idexes do you have on this table? If the dbms engine is doing a full table scan, it will completely load a cpu and take a long time. If you have a 2 cpu system and all your data is in RAM, then you'll see 50% cpu usage.

Please create and index, such as

CREATE INDEX BlueBoxEngineDB.TransferIdx1
ON BlueBoxEngineDB.Transfer(Amount,FromUserId,Status);


and then run again your query. It should complete in a glimpse.