SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fd60974a6c35a747311dbe5dfc02ba0cc9dd42a3cb79aebb5499399b303796d' 
  AND token = 'tg8ZR7kM6Md+v+FfwQ4upMSSnNXg/Kf8m/OPikclkyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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