How can I use MD5 CON SALT in Laravel

I am working on an application in laravel that connects to a database of another platform that is in MOODLE. Anyway .. I'm trying to make a login, for that I point my model User.php to the table mdl_user .. This login I had already done one time for another platform but I think this is different .. well I think it does not use simply MD5 to encrypt your keys .. I read in the documentation of moodle 2.4 that use MD5 with salt. I really do not know him because I'm new to all of this. My question is, how can I make Laravel read the hash that is in md5 with salt? or is there a magic function in laravel that reads all the hashes that exist haha ?, any help serves me .. Obs: Do not ask me to use bycript, I know it's safer but it's requested by the client, thanks My model is:

<?php

namespace App;

use Illuminate\Foundation\Auth\User as Authenticatable;

class User extends Authenticatable
{
    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $table = 'mdl_user';
    protected $fillable = [
        'name', 'email', 'password',
    ];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
        'password', 'remember_token',
    ];
}

And this is my EloquentUserProvider that I modified to work with md5

public function validateCredentials(UserContract $user, array $credentials)
{
    $plain = $credentials['password'];
    if (md5($plain) == $user->getAuthPassword()) {
        return true;
        # code...
    } else {
        return false;
    }
    // return $this->hasher->check($plain, $user->getAuthPassword());
}