torch
苣 centers on a torch: a handheld source of fire or light used for illumination.
The origin of 苣 is uncertain. It combines the plant radical 艹 with 巨, but the historical development is unclear.
The top plant radical 艹 suggests a bundle of reeds or grass, and the bottom 巨 looks like a large container. Imagine a torch made from a bundle of plants held in a large holder.
For キョ, picture a giant key-shaped torch lighting the way: key -> キョ, and the torch is as big as the 巨 component suggests.