PHP/AJAX Login taking very long
<form name="login-form" onsubmit="return false">
            <input type="text" id="the_username" value="Username" onfocus="emptyUsername(this);" onblur="clickrecall(this,'Username')"  class="focusfield input push"  />
            <input type="password" id="the_password" value="Password" class="input" onfocus="emptyPassword(this);" onblur="clickrecall(this,'Password')" />
            <span id="dialog-login-fail" title="Login failed"></span>
            <input type="submit" onclick="javascript:void(0);"  id="loginBtnBre" class="sign-in signin-submit-btn" value="Login Now" />
 </form>

<?php
require 'config.inc.php';

foreach($_POST as $k=>$v)
{
$_POST[$k] = trim($v);
}

if(!isset($_POST['theusername']) or !isset($_POST['thepassword']))
{
    print "Please use all fields";
}elseif(empty($_POST['theusername'])){
    print "Please enter a username";
}elseif(empty($_POST['thepassword'])){
    print "Please enter a password";
}elseif($_POST['theusername'] == "username" && $_POST['thepassword'] == "password")
{
    print "Password & User cannot be the ones already listed";
}elseif(!preg_match("/^[a-z0-9]+$/i", $_POST['theusername']))
{
    print "Please use only characters and numbers for username, no spaces, dashes or others!";
}else{

    $password = md5($_POST['thepassword']);
    $user = $_POST['theusername'];

    $loginVar = $usersClass->login($user, $password);

    if(is_array($loginVar))
    {
        $_SESSION['loggedIn'] = $loginVar;
        @session_regenerate_id(true);

        print "success";

    }else{
        print "Whoops, something went wrong! Try again.";
    }
}

?>

public function login($username, $password)
{

    $rs = mysql_query("SELECT `id`,`active` from `$this->usersTable` WHERE
        `username` = '".mysql_real_escape_string($username)."' AND
        `password` = '".mysql_real_escape_string($password)."'");

    if($rs) {
        $row = @mysql_fetch_object($rs);

            return $this->userInfo($row->id);

    }else{
        return false;
    }

alter table `TableName` add index `username` (`username`(500));
alter table `TableName` add index `password` (`password`(500));