SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '019c949a8bf387b2ded622cd875d26de179afc06fd57d65f48351c187c35f05c' 
  AND token = 'uIeCwNfwTrJTTNxnT6dI3yH06G6mSx8yzoGcrZ/JHp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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