Problem with ctools_export:metatag_config query

Hi,
I tried using Meta tags on my site. I have a bunch of modules, with views, ctools, locale, i18n, Entity translation, etc...

I've noticed that my site had become really slow, on the initial http request. So I've checked queries with the debug tools. And I had two very long queries associated with ctools. The more problematic one was ctools_export:metatag_config.

I suppose this is somehow related to Meta tags module, cause the problem disappeared after disabling it.
The slow query could reach the peaks of several seconds !!!

Thanks for any suggestion, patch, etc...