SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47444b822902f8b772c0edd4f894102ebe8ccf25fae31a386952a0a575f2ced8' 
  AND token = 'lKLMxetdRppbXMGVYJGE0DXMekwhKiLcMe1HB2dX9PI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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