SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11574575f3f769f3d4f73e69786851c6cb356deef68f27169d830743966f3c50' 
  AND token = 'FsIWkOKDviovbkiHUXI8LfxvkaUnMHV7xBxLzkkRqaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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