The actor made the comment while promoting his new project, Brothers, alongside costar Woody Harrelson. Brothers includes a governor storyline that fueled fresh questions. He told the outlet the plotline wasn't inspired by the rumors, it was the other way around, saying "that governor stuff was all real" before the show existed.
The comment does not confirm or rule out a future campaign. It keeps McConaughey's political intentions exactly where they've been for years, unsettled and open to interpretation. Fans and reporters got another quote to parse, but nothing resembling a real answer. Harrelson's presence in the interview kept the tone light, tied to the two promoting their film rather than staging any kind of political announcement.
McConaughey has flirted with the idea of Texas office before without committing to a run, and this answer fits that pattern. Two words, "not yet," leave the door open just enough to keep the speculation alive.