cakes made from rice flour twisted into rings
粔 centers on a specific type of traditional confection: cakes made from rice flour that are twisted into ring shapes.
粔 combines 米 (rice) with 巨, which likely contributes the sound and may relate to the twisted ring shape. The exact historical development is uncertain.
The left side is rice 米, and the right side 巨 looks like a giant twisted ring. Picture giant rings of rice flour dough twisted into cakes.
For キョ, imagine a giant key-shaped rice cake twisted into a ring: key -> キョ, and the key unlocks the taste of the traditional sweet.