checkbox fields are stored as serialized arrays in the database. Try putting ” around the search value. This is shown, but not very obvious under QUERY POSTS
on this page Query http://www.advancedcustomfields.com/resources/checkbox/
$args = array(
'numberposts' => -1,
'post_type' => 'restaurant',
'meta_query' => array(
array(
'key' => 'restaurant_assets',
'value' => '"'.$restaurant_assets.'"',
'compare' => 'LIKE'
)
)
);