http://www.chess.com/forum/view/livechess/new-logic-for-auto-pairing-and-seek-graph
And
https://support.chess.com/customer/portal/articles/1622811-how-are-seeks-matched-in-live-chess-
Short answer? Go to the drop down time menu. Choose Custom. A rating options button pops up. Click and enjoy.
in the live chess - play live chess - new game in my screen don't shown the options (min rating:, max rating:, and rate game). My OS is windows 7. It happens in the explorer and the google chrome.