Aliexpress
Click here… to search for Xiaomi Gaming Keyboard on Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (52.19 USD): AFfbG10
Coupon (53.93 USD): aff7off
(CouponsFromChina.com tip: this code has to be applied in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): 24f401, 4d8a18, e2bcea, 502C6B, 19b864, TTxBG10, e18b44, BGss506
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Here is price history (for all/most countries) for Xiaomi Gaming Keyboard.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).