Event query with all age group conditions

// WP_Query arguments
$args = array(
	'post_type'              => array( 'event' ),
	'post_status'            => array( 'publish' ),
	'meta_query'             => array(
		'relation' => 'OR',
		array(
			array(
				'key'     => 'age_group_from',
				'value'   => '$ageMin',
				'compare' => '<=',
			),
		),
		array(
			array(
				'key'     => 'age_group_to',
				'value'   => '$ageMax',
				'compare' => '>=',
			),
		),
		array(
			'relation' => 'AND',
			array(
				'key'     => 'age_group_to',
				'compare' => 'NOT EXISTS',
			),
			array(
				'key'     => 'age_group_to',
				'compare' => 'NOT EXISTS',
			),
		),
	),
);

// The Query
$query = new WP_Query( $args );