SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '52d792cb680034cc6afc17e5fe887a4ac73a6865e231c78261de097b9a226456' 
  AND token = 'mkLIZbj4+ZrwSeSO1x+aRAFc5HCQu9DT//g7DCCXimA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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