Upon the approval of the governing body of the municipality and of the county quorum court if county funds are used to partially pay the salary of the judge of the municipal court, any judge of a municipal court who has served or who shall serve at least twelve (12) years in office as municipal judge and who has also served four (4) years or more as city attorney in the same city shall, upon attaining age sixty-five (65), receive retirement benefits for and during the remainder of his or her natural life in an amount equal to one-half (½) of the salary payable to him or her at the time of his or her resignation, retirement, or succession in office.