Miss. Code Ann. § 7-9-3

It is not lawful for the treasurer or any other person to enter or be in the treasury department between sunset and sunrise, except in case of fire or other like urgent necessity. At five o’clock or sooner in the afternoon, the vaults shall be closed with a timelock set to open at nine o’clock in the forenoon of the next day, unless it be a Sunday or holiday when it shall be set, if possible, to open at that hour on the next business day. During business hours the timelock shall be so adjusted that a person in charge of the office can instantly lock the safe or vault.