Okla. Stat. tit. 46, § 46-18: Certificate of county treasurer

The Secretary of State shall not receive for record or for

filing any mortgage, deed of trust or instruments supplementary

thereto or amendatory thereof, described and covered in Section 1

hereof, unless and until the same has thereon the certificate of a

county treasurer that the same has been presented to him under the

provisions of the Real Estate Mortgage Tax Law, Title 68, Sections

1171 - 1182, O.S.1961, and that any real estate mortgage tax, if any

is due, has been paid or that none is due thereon, as the case may

be.