SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e936042cba302fe8172053609c516eca8f25e4d297ee53dd7b10cfbe28387904' 
  AND token = 'pG3huSfuSoURKas3v3TAQLUeBdH/huFodv6TQU6c4M8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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