combined metas

$meta_query = array(
	'relation' => 'OR',
	array(
		'relation' => 'AND',
		array(
			'key'     => 'restricted_access',
			'value'   => '1',
			'compare' => '=',
		),
		array(
			'key'     => 'allowed_user',
			'value'   => 'currentUserID',
			'compare' => '=',
		),
	),
	array(
		'relation' => 'OR',
		array(
			'key'     => 'restricted_access',
			'compare' => '=',
			'type'    => 'CHAR',
		),
		array(
			'key'     => 'restricted_access',
			'compare' => 'NOT EXISTS',
		),
	),
);