SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cf8004a66e3cdeb1b9959d6ae5df0aadcb049d2b699efa53a7c60c3762243fd' 
  AND token = 'NmaRUR3zYF5hzbsjEdvMP05uzAkKONZgk/mdrBdIhcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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