POST request with the REST Client extension for Visual Studio Code

I'm using the "REST Client" extension for Visual Studio Code https://marketplace.visualstudio.com/items?itemName=humao.rest-client.

I'm able to make a GET request with this code:

GET https://some.domain.com/search/someuser/somekey?foo=5&bar=1

and it works.

Now, I need to make a POST request and pass the foo and bar values as form fields.

I tried with:

POST https://some.domain.com/search/
Authorization: Basic someuser somekey
Content-Type: application/x-www-form-urlencoded

'foo'='5''bar'='1'

but I'm getting back an error "Missing required parameter foo in the post body"

What is the correct syntax for a POST request with REST Client?

Thanks.