When you use an exchange provider (such as MEXC Global, Bittrex Global, Hotbit, etc.) the transactions are usually carried out within 1 or 2 minutes. In rare situations the transaction time can even significantly exceed this time, ie. in case of systems maintenance or unexpected technical issues on the side of the exchange provider.
The reason is that exchanges to not perform transactions immediately when you execute them. This means that transaction are queued for processing and only when the backend of an exchange provider is ready to conduct a transaction, it will finally use the Electra Protocol blockchain for execution.
The speed of a transaction from an exchange to XEP Wallet transaction is entirely related to the processing speed of the respective exchange. Once a transaction is posted by the exchange to the Electra Protocol blockchain, it is executed in near realtime.