476.470.  Judge not eligible for retirement, when. — Any judge retiring from office under the provisions of Section 27, Article V of the Constitution of Missouri, shall not be eligible for the retirement provided by sections 476.450 to 476.510 during the period of his compensation under such constitutional provisions, but upon the completion of such period he shall be and become eligible for the retirement privileges provided for in sections 476.450 to 476.510 if he be otherwise qualified as to age and length of service.