No, overclocking (OCing) has nothing to do with your latency in game. In basic terms, OCing increases the power of your processor.
Your ping is solely dependant on your internet connection. Since you mentioned WoW, you might want to consider which server you play on because of different data center locations. If, for example, you live on the East Coast and you choose to play on the server that is housed in the West Coast data center, your ping will suffer. Similarly, if you play US WoW and choose to play EU WoW your ping will be way higher due to distance.
To check your server, google "WoW datacenters" and fine a list of servers and which datacenter/location they belong to. The farther the datacenter away from you, the worse your latency will be.
Server location being one of the factors, you might want to check if anyone else in your household is using the internet when you play. If someone (or yourself) is downloading torrents or is streaming youtube/movies, you will experience lag. Also, your internet connection package might be weak (in terms of speed) and, if you decide to upgrade, you will notice improved latency in games.