woothemes/woocommerce — pull request #5550 by PlacidBox (2014-05-24 04:09:25+00:00)
Title: Fixes performance degredation on large wp_options tables

Recently fixed a family member's site where these queries were taking approximately 8 seconds each. Mysql won't use the index on these deletes due to the underscores in the LIKE expressions. You want actual underscores there though, not the single character place holders.

Correcting gave approx. 100x speed up to the site