Have you tried using a VPN?
When I turn my VPN on, the pings on the master server drop to normal levels. I'm not sure why... for example, TAW has 4 servers on the same physical server in Canada. From the main multiplayer server list, i'll see 3 of them at about 50 ms, and on the 4th, i'll be at 500+ ms. Makes no sense to me... but when i turn on the VPN, they're all the same.
You can also just connect directly to the IP and the ping will normalize.
tl;dr the ping list on the master server list doesn't always sync with your ping to the actual MP server.