แก้ไขโค้ด login งงมากช่วยหน่อย

<?php
require 'connectdb.php';

$login_username = mysqli_real_escape_string($dbcon,$_POST['username']);
$login_password = mysqli_real_escape_string($dbcon,$_POST['password']);

$salt = "yingyeenddldk[l[l[ljihhduhudf";
    has_login_password = hash_hmac('sha256', $login_password, $salt);

    $sql = "SELECT * FROM tb_login WHERE login_username=? AND login_password=?";
    $stmt = mysqli_prepare($dbcon,$sql);
    mysqli_stmt_bind_param($stmt,"ss",$login_username,$has_login_password);

    mysqli_execute($stmt);
    $result_user = mysqli_stmt_get_result($stmt);
        if ($result_user->num_rows == 1) {
        session_start();
    

        $row_user = mysqli_fetch_array($result_user,MYSQLI_ASSOC);
        $_SESSION ['login_id'] =  $row_user['user_id'];
         header ("Location: main.php");

    }else{
        echo "no no";
    }