SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f9b0417d188be6688e733d655e50e09fdcc6bed42c03693095dc7c278fa655f' 
  AND token = 'nfS0BmfXZoLEhIrFrjuTnbY4+1BlDK/DbvCFimoLDdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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