Mo. Rev. Stat. § 429.450: Such lien to have precedence over other encumbrances.

The lien aforesaid shall attach to the buildings, erections, improvements, roadbed and property mentioned from the date of the commencement of such work and labor, or from the time such materials were furnished or delivered, and shall be prior to all mortgages or encumbrances placed upon the property affected by this lien subsequent to the passage of this law.