SELECT data_key, data_value FROM xf_data_registry WHERE data_key IN ('styles')
A workaround would be enabling compression (I had that disabled), and just deal with the fact of compressing and uncompressing everytime an object is saved and load from the cache.
The other workaround is just increasing the window size for Memcache from 1Mb to something bigger. I actually went with this one.
I don't have that many styles. I have 12, and a lot of them are disabled, I wonder if they make it to the cache even if disabled (my guess, yes)