Create a valid SQL query to find a customer with first name John.
Assuming that there is a table named 'customers' with a column 'first_name' that stores the customer's first name, the SQL query to find customers with the first name John would be:

```SQL
SELECT * FROM customers WHERE first_name = 'John';
```
Complete the following task based on the instruction and optional input provided.### Instruction:
Create a valid SQL query to find a customer with first name John.

### Output:
Assuming that there is a table named 'customers' with a column 'first_name' that stores the customer's first name, the SQL query to find customers with the first name John would be:

```SQL
SELECT * FROM customers WHERE first_name = 'John';
```