How to skip "Checked available update data for" all modules when I just want to update core or a specific module? I'm upgrading a lot of my Drupal sites to 7.32. Unfortunately it takes a lot of time for each site because of some update check that I don't need.

On How to upgrade only core with drush? I learned I can use drush up drupal to only upgrade core. But unfortunately drush is still checking a lot of statuses, which takes a long time for every site:

Checking available update data ...
Checked available update data for Administration menu.                                                                                                                                                                         
Checked available update data for Admin VBO Views.                                                                                                                                                                                 
Checked available update data for Advanced CSS/JS Aggregation.                                                                                                                                                                     
Checked available update data for Block.
...


How can I skip this? I just want drush to fetch 7.32, check if the site is still functional and head to the next site.
Drush calls Drupal code to update the list of available releases, so regrettably there is no way to update the release info for just some subset of available projects.