The register of deeds of each county shall prepare and keep in his office a tax lien index book which provides:
The register of deeds shall endorse on each notice of lien the day, hour, and minute when received, index the notice in the tax lien index book and record the lien in the manner provided for recording real estate mortgages. Upon payment of the tax, penalty, and interest the secretary shall file a notice of satisfaction with the register of deeds, who shall file such notice in his office and indicate such record in the lien index. The filing and recording of the liens and satisfaction is done at no cost to the state.
SDCL 10-59-12