Hashkey has not been featured for hash rates despite being an exchange, and it neither has the keys to your golden gates (it means, financial freedom). This exchanged has been declared Officially abandoned. Since then, many have been the researchers who have established negative reviews about it.
The most important reason to know is that this exchange has never received the appropriate support it deserved. And as a consequence, it started to slow down its receptivity for sales until becoming an unreachable page.
Now, if you want to know more about this project, you must access official markets like The CoinMarketCap where they save a little reliable information about the platform. Hope this could help you to find the content you need to understand the scope the team planned to reach.