This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 踁 is uncertain. It visually combines 足 (foot) with 巠, but the original semantic and phonetic roles are unclear.
With 足 (foot) on the left and 巠 on the right, 踁 might relate to a foot or leg action, but its meaning is too obscure for a reliable mnemonic.
For ケイ, imagine a foot (足) kicking a heavy key (ケイ) that is stuck in the 巠 component: the key sound cues ケイ.