The sha1 hash for 64test64xa is 6779c53432b8badf049bb9d8924a5785dd887243 which is 41 characters only using hexadecimal, 10digits and 6letters. But how long it would be if it was using the whole 26 letters in the latin alphabet? What if it also differentiated between UPPER and lower cases?
There’s also a Base64URL variant that is a little more friendly in the modern world where the
+/=often need escape sequences.The first two are replaced with more sensible characters and the third is just removed entirely - do you really need padding?