SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47ed36a48fc5aae66689f10200cb40a10a8acbaf6797ad93307adb85f3dd5922' 
  AND token = 'iw+qvWcSSgoMtBtgFmVq21jhkzmRgpOXK5AiTMkhot4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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