This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
鞿 combines 革 (leather) with 幾, which likely contributes a phonetic element. The exact historical development is uncertain, and the character is rare in modern use.
With 革 (leather) on the left and 幾 (how many) on the right, picture a leatherworker wondering how many pieces of leather are needed for a project. The meaning is uncertain, so treat this as a visual placeholder.
For キ, imagine a leather keychain: key -> キ, and the leather 革 component ties it to the kanji.