SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f33f5475c04a13cd9b3832fe4fc41dba8a1df97a577e71fe9e8035d73aac8192' 
  AND token = 'f6ynF/nwokZIiGlQ0epFvBIyx7rIbPtgjrlC5QhLn+M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}