The story goes like this: it was reported that JD.com had "sold" 1 million pre-orders for the Nokia X in just 4 days, and 10 million within a week. The trouble is that pre-orders don't work the same way in China as in the U.S.. In China, there is no actual commitment to buy when placing a pre-order, and no money is exchanged. It is more of a reservation system, and the purchase is completed at the time of release.
That leads to today, when the device was actually put up for sale on the website at 10AM Beijing time. JD.com is saying that the first batch of Nokia X smartphones sold out (with actual money-exchange sales) in just 4 minutes. But, the caveat here is that there is no indication how many units were in that first batch. JD.com had a promotion for the first 10,000 purchases, so it is more than that, but as for how many more, we don't know.
Either way, there is certainly quite a bit of interest in the device from the Chinese market, so it is fair to assume that the sales of the Nokia X will be respectable, which is good news for Nokia's first Android device. The next batch of Xs go on sale March 31st in China, so it will be interesting to see what happens then.