Mo. Rev. Stat. § 1.160: Effect of repeal of penal statute.

No offense committed and no fine, penalty or forfeiture incurred, or prosecution commenced or pending previous to or at the time when any statutory provision is repealed or amended, shall be affected by the repeal or amendment, but the trial and punishment of all such offenses, and the recovery of the fines, penalties or forfeitures shall be had, in all respects, as if the provision had not been repealed or amended, except that all such proceedings shall be conducted according to existing procedural laws.