SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec252a8e183e1ab78093de1d53c80c9c436ff6df174d8ce3df5687ea2f7e2c4f' 
  AND token = '8XuPeNl+pj/ig5Cvj7/4TTPGcM6KhvfnNl4FoYSpZJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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