const response = await fetch('https://service.pcibooking.net/api/payments/paycard/tempsession', {
  method: 'POST',
  headers: {
    'Authorization': 'APIKEY your-api-key'
  }
});

const sessionToken = await response.json();
console.log(sessionToken);

import requests

response = requests.post(
    'https://service.pcibooking.net/api/payments/paycard/tempsession',
    headers={
        'Authorization': 'APIKEY your-api-key'
    }
)

session_token = response.json()
print(session_token)

"1a75885fabe443588488de7d7e7f9980"

{
    "code": -1003,
    "message": "Not authorized to access this resource",
    "moreInfo": "Bad or missing authorization data, expected APIKEY",
    "errorList": null
}