Wp_query with 2 meta keys and array of meta values

I think you need to do something like this:

<?php
$args = array(
    'post_type'         => 'shop',
    'post_status'       => 'publish',
    'posts_per_page'    => -1,
    'meta_query'        => array(
        'relation'      => 'AND',
        array(
            'key'       => 'cu_status',
            'value'     => array( 'pending', 'processing' ),
            'compare'   => 'IN',
        ),
        array(
            'key'       => 'cu_date',
            'value'     => array( '2016-01-12', '2016-01-13' ),
            'compare'   => 'BETWEEN',
            'type'      => 'DATE'
        )
    )
);
?>