About 1827. Jane Loudon's The Mummy! A Tale of the 22nd Century is the earliest speculative fiction I can find that pictures a future of changed and advanced technology and society. Others like Shelley's The Last Man picture a future where everything of technology and even costume is unchanged, with some political changes that form the ambitions of leading men. But Loudon pictured a world, not only with steerable balloons but small one-man LTAs that were ridden, ladies wearing court trouser outfits with gas-jet hair ornaments, steam plows and steam mechanical guards patroling the prisons, the servant class highly educated in proper language and science, but no brighter in applying them (you can educate people but can't give them common sense), and England, having dropped its monarchy, have returned with a rule of virgin queens whose nieces inherit the crown.

In short, the first future that's changed in a lot of ways, and not just in political arrangements.

I have never found a serious "vision of the future" from earlier, though I haven't read everything. There are a couple of slight possibilities from the late 1700s. There are any number of Utopias laid out, from the time of the tale of Atlantis, or the description of The Republic,, but that was present or past tense, not predictive.