All cities and towns of this state operating under charters granted directly and specially by the general assembly prior to the adoption of the constitution of 1875 are hereby defined and declared to be cities and towns under special charter, and all laws now existing or which may hereafter be enacted relating or making reference to cities or towns under special charter or special charter cities or towns shall be deemed to and shall apply and be valid in relation only to cities and towns of this state defined and declared in this section to be cities and towns under special charter.
§ 81.010, RSMo