If the field bustype is a select field then it stores an array of values and you must do a "LIKE" meta query.
....
'meta_value' => $metavalue,
'meta_compare' => 'LIKE'
....
This would be event better
....
'meta_value' => '"'.$metavalue.'"',
'meta_compare' => 'LIKE'
....
For more information on querying by different types of fields see https://www.advancedcustomfields.com/resources/query-posts-custom-fields/
