SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '366c211431a8b2847b3ccea36534ae020a46691e42837f55732a80487ef5a797' 
  AND token = 'nnHHu3trBoTvVv/DaTdoTKfF1N40xRhiDoDIdXKRHOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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