如何使用PHP中数组中另一个键的值获取键搜索的所有值？

I have a table with the types of cars that I have on stock:

Table cars

idCar  |  name
-------+-------
1      |  car1
2      |  car2
3      |  car3
4      |  car4

And another table with the customers that have bought each car:

Table sales

idCar  |  idCustomer
-------+------------
2      |  cust1
2      |  cust5
3      |  cust5
3      |  cust2

and I have all the values of sales table stored in an array with PHP. It looks like this:

array(4) { 
      [0]=> array(2) { 
          ["idCar"]=> string(1) "2" 
          ["idCustomer"]=> string(5) "cust1" 
      } 
      [1]=> array(2) { 
          ["idCar"]=> string(1) "2" 
          ["idCustomer"]=> string(5) "cust5" 
      } 
      .... //Here the rest of values
}

What I am trying to do is to get all the values of a car (or cars) that have been bought by a particular customer, for example, cust5.

So, if I search on the sales array for the cars that have bought the customer cust5 it should return to me, idCar with the values 2 and 3. After I will get the values of idCar and name with MySQL with that values.

I have tried using the following sql statement:

"SELECT * FROM cars WHERE FIND_IN_SET(idCar, $salesTable)";

where $salesTable is the array that contains the full sales table but of course it does not work because I am trying to parse there an array directly, instead of the values of idCar.

I would like only to pass to the sql statement the values of idCar that match with a particular customer, in this case, with cust5.

Is there some way to get only the values of idCar required with some function of PHP giving only cust5 as parameter so I would be able to apply the sql statement that I put above?

Thanks in advance!