Some writing surfaces existed, more like an easel than a table though.
https://www.artdisplay.com/Shared/SiteImages/Easels%20by%20Amron/History/History%20of%20the%20Easel%203.jpg

and

https://cowofgold.wikispaces.com/file/view/82127479.jpg/241544879/346x200/82127479.jpg

Even as far back as ancient Egypt.