AliExpress only deducts the agreed amount of the order, which is indicated on the checkout as well.
Possible reasons for the exceeded amount are:
1. exchange rate has changed.
2. Commission fee taken by your bank or card company.
3. Your bank converts the currency for you to proceed the payment. For instance, your card only supports USD transactions while the order should be paid in RUB. As a result, extra funds may be required for the conversion.
To figure it out, you may contact the bank to check the transaction details.