It looks like it's a combination of
Keisha and
Asha.
Keisha is a variation of the name
Keziah, which means "favorite" in Swahili or "cassia" in Hebrew. I believe that I've heard that
Keisha may be a variation of
Aisha, but I'm not entirely sure.
Asha means "hope" in Sanskrit or "alive" (or "life") in Arabic.
Asha can be a variant of
Aisha (which means "alive" or "life" in Arabic.