SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e83d221351c604723c5a135402809c0e60b0e517a5f6d0961dcb49b93fca90b6' 
  AND token = 'hz5ZIEfoVSArFd3omfK1TjuZxzfEujjWfV0JWJTi/0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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