SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31bd73cd185824d2733bc26b251aaaf83d7bad81e3d8200de8ba2eb74ee1fd77' 
  AND token = 'xpzK9XituwHWSlLkS5Dj/7QyLA4kHo8yybW/maPiVDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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