Filter posts by multiple checkbox categories

I thing, you should use this code for filter the check box category

<?php // cat 42=Laos      cat 57=2-4Days
    <?php $my_query_1 = new WP_query(array('category__and' => array(42,57))); ?>
    <?php while ($my_query_1->have_posts()) : $my_query_1->the_post(); ?>
    <a href="https://wordpress.stackexchange.com/questions/100169/<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to
    <?php the_title(); ?>"><?php the_title(); ?><?php the_excerpt(); ?></a>
    <?php endwhile; ?>