as at today/ to date/ Right now

“As of” means “at the time of.” You can say exactly what you wrote at the end, and you should. As already posted more than once, “as at” is simply not something we would say or write. I don’t know where you saw it, but it was probably either written by someone with a different native language or an error.

You also asked about “to date” in the original post. It means something different. It means “until now.” It differs from “as of” because (a) it refers to a time period, not a specific instant, and (b) because that time period ends now, not at a stated time. You could write “To date, the value of the GBP has never been below US$1.” (I think that’s true, but this is about language, not rates of exchange.)