Custom Search | check multiple meta_value for search value

You can use meta query as give below:

$args = array(
    'post_type'         => 'location_type',
    'posts_per_page'    => 10,
    'post_status'       => 'publish',
    'meta_query' => array(
        'relation' => 'OR',
        array(
            'zip'     => 'zip-value'
        ),
        array(
            'town'     => 'town-value'
        ),
    ),
);