SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0dc74fbab3e7164e65181131e29ed5f2d1df881e8427f6976a2f74ddb69b388' 
  AND token = 'SHYpVRW0AniBmLw1ZqKRvb4iZoU6IwYMd2oFfymaU5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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