Notwithstanding any other provision of law, the commission may, in its discretion, open for business on any Sunday or legal holiday any state liquor store located on a main route where traffic is heavy; provided, however, that no state liquor store may be opened for business at any time on Easter or Thanksgiving day, whenever appointed, and Christmas day. Although full-time employees shall be given the option of working, no such employee shall be required to work on such days. The commission may employ part-time employees, subject to the rules of the director of personnel, to staff stores open on Sundays or holidays. Any full-time employee who works on such days shall be paid 1-
1/2 times the employee’s regular rate of pay for the actual number of hours worked.