It's fine to treat "hihowareyou" or "heyhowsitgoing" as a word that literally just means "hi". It's never a real question; it's an automatic fixed expression for us. "Good" is the customary response (doesn't matter if it's true), but ignoring the question and just saying something like "Hey, what's up?" or "Hey, how can I help?" is also a fine response that invites them to skip any other smalltalk they might have planned. This is especially a handy approach for typed chats.