SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8af04abd696f3683c45ac8037e523191c75d6fc41a9ed7ee3e1c5394a32f7219' 
  AND token = 'ZaLi5FGOKDuzhdUgRYs2BuIQBE4M+BqPW2QmWTkHka4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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