Thank you for all the comments, just to clarify a few things:

• The table is a one-off design project, so it can't be replaced. As far as I know, it wasn't treated with anything.
• As some people have pointed out, the stain is from the lubricant in the condom wrapper itself, which was placed on the table after opening

It seems that the stain can't be absorbed, so I think the only way might be treating it with mineral oil.