SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f813065fd7f51a144365eda1d88009f191c2db400c3155c229fbf15106e2e4bd' 
  AND token = 'rc5ymHtE53+uP/J+8TObNavvUP6kBo+a3HmJM8AmGPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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