Using If and Vlookup Statement together

I am trying to change the Master Key to a “new key” if the origin and destination match the old key.

Basically the master key from table 1 will look to see if the key exsists in Table 2, if it does it will pull the new Key. If the master key does not exist in Table 2 it will not change. It will be the original origin and destination. I have tried using if statements with vlookups however I am getting stumped with the logical error. Does anyone know how to return the new value or if there is another way to solve this?

I have attached an example. In the example, in table 1 the Master key is made from London and Italy together. This master key needs to be looked up in Table 2 (located in Column A) If it’s there it will pull the New Key (Column D).