At this moment you can trade bkx at forkdelta exchange, the link is here https://forkdelta.app/#!/trade/BKX-ETH but there is no volume at all. if you want you can make deposits and place a buy/sell order.
It will be nice if you complete the swap first. For the swap most of the exchange stop trading of BKX coin. so will suggest you to do swap of your BKX coin fro TNC coin. BKX coin was listed at bittrex, they also publish a article regarding the swap, you can read it from here: https://bittrexglobal.zendesk.com/hc/en-us/articles/360013835980-TNC-Support-Instructions-for-Bankex-BKX-Token-Holders-to-Swap-to-TNC-Group-Token-TNC-