I’ve mostly encountered this use case when making an “event” custom post type: the client wants to see only events ‘in the future.’

This assumes that our date is in the future (where date_time is the ACF field):

$today = date('Y-m-d H:i:s');

$args = array(
	'post_type' => 'event',
	'posts_per_page' => 10,
	'paged' => $paged,
	'order' => 'DESC',
	'orderby' => 'date_time',
	'meta_key'  => 'date_time',
	'meta_query' => array(
         array(
            'key'       => 'date_time',
            'compare'   => '<=',
            'value'     => $today,
        )
    )
);