SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd546c647678bc7b7ea865081dbe1d53a4c895af270402be414e507932acc1f6f' 
  AND token = '1CYX2KaUAZ6J+9vkUKpYPjXRpXUlcD1xsN+uNBPq6b4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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