$args = array(
                        'posts_per_page' => -1,
                        'post_type'      => 'product',
                        'meta_query' => array(
                            array(
                                'key' => 'teach__timer',
                                'value' => $date_now,
                                'compare' => '>',
                                'type' => 'DATETIME'
                            ),
                        ),
                        'order'          => 'ASC',
                        'orderby'        => 'meta_value',
                        'meta_key'       => 'teach__timer',
                        'meta_type'      => 'DATETIME'
                    );