Thornton, 29, is accused of using the Internet to entice a 15-year-old minor for sex.
The charge came out of Lee County.
Thornton entered his plea Thursday before Magistrate Judge Jenny Virden, who set his unsecured bond at $10,000.
If convicted, he faces from 10 years to life in prison.
Thornton was indicted Jan. 23 but it became public Thursday.