SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae55a95209c408a326905ee4faad85d6a30dc8f1b9836d90df5d5e7c693b6fdf' 
  AND token = '3oZP8ZuHgZgvQAZ1K8dwEkbV6hiqv0mz+JI89nZNDj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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