wp_enqueue_media taking 50 seconds to load

There seem to be many posts about timeouts and extreme slowness since upgrading to 4.2.2 – with many solutions that work for some but not everyone. In my case, running Query Monitor the problem seems to be with wp_enqueue_media calls. Here is the actual text from Query Monitor – does anybody have a solution? Anything at all???

SELECT ID
FROM wp_posts
WHERE post_type = 'attachment'
AND post_mime_type LIKE 'audio%'
LIMIT 1	wp_enqueue_media-
include('wp-admin/edit-form-advanced.php')
45.5844
SELECT ID
FROM wp_posts
WHERE post_type = 'attachment'
AND post_mime_type LIKE 'video%'
LIMIT 1	wp_enqueue_media-
include('wp-admin/edit-form-advanced.php')
46.6395