SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a345d1fef74bcc6a8ae13d656c95e00efee65da675b41a4bf6505576538ec2a' 
  AND token = 'xCzWaOFiBabYw5xOKhohILgnw28EMXlrEu8/+V6uI58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}