Yii2 today scope in ModelQuery

UserQuery.php

<?php
namespace app\models;

/**
 * This is the ActiveQuery class for [[User]].
 * @see User
 */
class UserQuery extends \yii\db\ActiveQuery
{
    /**
     * @return $this ActiveQuery
     */
    public function today()
    {
        return $this->andWhere('date(starts_at) = date(utc_timestamp)');
    }
}