curl --request GET \
  --url https://api.xpaycheckout.com/s2s/customers/{customer_id}/tokens \
  --header 'Authorization: Basic <encoded-value>'

{
  "customer_id": "cus_Tfd3Jq1tZxPjYVhRQW2r3",
  "tokens": [
    {
      "token": "tok_4xK2Nm1tYwOiXUgPQV1r2",
      "last4": "4242",
      "brand": "visa",
      "exp_month": 12,
      "exp_year": 2025,
      "created_at": 1728127800000
    }
  ]
}