This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
樻 combines 木 (tree/wood) with 貴, which likely contributes a phonetic element. The exact historical development is uncertain.
With 木 on the left and 貴 on the right, picture a precious wooden box made from a rare tree. Since the meaning is uncertain, this image can help remember the shape without a fixed meaning.
For キ, imagine a key (キー) made of wood from a rare tree: key -> キ, and the wooden key opens the precious box.