$args = array(
	'date_query' => array(
		array(
			'hour'      => 7,
			'compare'   => '>=',
		),
		array(
			'hour'      => 10,
			'compare'   => '<=',
		),
	),
	'posts_per_page' => -1,
);
$query = new WP_Query( $args );