Rooting an ASUS K012
Since it's lollipop you'll have to unlock the bootloader before being able to root.(warranty will be void)
Then you can download a compatible recovery and flash it using fastboot.
You can then use the recovery to install su.
Caution: Unlocking bootloader will clear all the data from your tablet. 
Lemme know if you understand the risk and are willing to do it. I'll write a guide for you if you want.
Here's a wiki link for unlocking the BL:http://wiki.cyanogenmod.org/w/Template:Unlock_Bootloader_Asus