How to filter a query by multiple meta keys and order by other meta keys

I’m trying to query posts using WP_Query and meta_query parameters:

$args = array(
    'post_type' => 'produkty',
    'meta_query' => array(
        'relation' => 'AND',
        array(
            'key' => 'produkt_aktywny',
            'value' => '1',
            'compare' => '='
        ),
        array(
            'key' => 'produkt_dostepnosc',
            'value' => '1',
            'compare' => '='
        )
    )
);

$query = new WP_Query( $args );

What should I add to order the results by two other meta keys ('produkt_kategoria' and 'produkt_cena')?