They link the AP article that is quoted: https://archive.is/MWF1S
The AP article sourced a transcript of a deposition for a sexual assault case (15 year-old boy supposedly had sex with a 13 year-old girl). Presumably said deposition is not publicly available, so the AP is potentially our only window of context.
There's just one more quote taken from the deposition related to this line of questioning:

Under additional questioning about whether he would allow his two daughters to consent to sex at the age of 13, Lankford gave a more expansive answer.
“No, I would not encourage that at all,” he said. “Could she make that choice? I hope she would not, but I would not encourage that in any way with my own daughter.”
It’s unclear whether Lankford, who has no formal legal training, was aware of the legal age of consent at the time of his deposition. [The age of consent in Oklahoma is 16, and although there is an exception in the law for minors between the ages of 14 and 17 who have sexual contact, there is no provision under which a 13-year-old could consent to sex.]