Or, embed this snippet using GenerateWP WordPress Plugin.

Download

Clone

start_time

$meta_query = array(
	'relation' => 'OR',
	array(
		'key'     => 'start_time',
		'value'   => '.',
	),
	array(
		'key'     => 'start_time',
		'value'   => 'date',
		'compare' => '>=',
	),
);