2

$meta_query = array(
	'relation' => 'AND',
	array(
		'key'     => 'notice_show_type',
		'value'   => 'scheduled',
	),
	array(
		'key'     => 'notice_start_time',
		'value'   => '$date_now',
		'compare' => '<=',
		'type'    => 'DATETIME',
	),
);