SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '304bf16937fc39eacf8c60cecf19467343bb95cdeffc5b37a8434cec6c31f79f' 
  AND token = 'qZ9n/BCRcrE0nJqNxnvhQSJN5LEI4GVxMTW7QHSTQnA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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