. . . "Notwithstanding section 3 of chapter 40 of the General Laws to the contrary, the board of selectmen of the town of Natick may lease, for a term not to exceed 99 years, including any extension or renewal terms, or convey the town-owned property at 5 Auburn street in the town of Natick, the site of the former Eliot Elementary School; provided, however, that the terms of any such lease or sale shall" .