$query->num_rows nothing returns

Within my model I have the following code but does not return anything (running the sql in the bank returns the record).
 
I also tried with $ query-> num_rows also, same thing ... what's wrong?

Code:

<?php
class login_model extends CI_Model{

    function ValidaLogin()
    {

        $query = $this->db->query("SELECT * FROM `usuario` WHERE `Usuario` = 'user' AND `Senha` = 'password'");
        
        if ($query->num_rows() > 0)
        {
           foreach ($query->result() as $row)
           {
              echo $row->usuario;
           }
        }