The clue is in the words
first purchase which places the action (asked) at a specific point, sometime in the past. The speaker doesn't provide the exact date because it was irrelevant to the discussion; however, he or she knows when the event occurred because the memory of which is fixed firmly in their mind. The episode of being asked to provide a scanned copy, definitely occurred sometime in the past.
It is therefore a completed action, and the simple past tense should have been used.
If it hadn't happened, why else would the author have warned about using a virtual card?
In the Active voice, you would say:
Aliexpress asked me for a scanned copy of my credit card with my first purchase
NOT “They have asked me for .... with my first purchase”
The Passive voice would be
I was asked for a scanned copy of my credit card by Aliexpress with my first purchase
The event of being asked to do something, happened the first time. Perhaps after the first time, a scanned copy was no longer required. But we cannot be absolutely certain because the author might have made only a single purchase using Aliexpress. On second thought, using first does imply that more than one purchase has been made.
Note, the present perfect tense is used here because although the act of purchasing has been completed, there is a strong likelihood that the author will continue to use his or her credit card in the future.
I don't know anything about credit cards and how they are used in the States, so I'm just going by what is written! :)
P.S. By the way, I've upvoted Robusto's answer because he is a native speaker, and he explained very well why the author used the passive voice.