Executive Producer is a broad term with broad meaning. Sometimes it's the actually shows creator or showrunner. Sometimes it's a money man. Sometimes it's honorary.
In this case, it's not just honorary. Overbrook owns the rights to Karate Kid and had to green-light the show. They were actually pivotal in getting it made. The initial pitch was to Overbrook who loved it and brokered the meeting with Sony. Smith himself has very little involvement but as the founder of Overbrook his position as Executive Producer is actually meaningful not just a tip of the hat.