SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bb6d127896146d0d2aafa518fc70ef43d6171d56f3ff36272c5b61e004f5d599' 
  AND token = '9WcDV1SL0d/5zPHgN2HRT/opV9Y5NQbD/n5bRt/9DwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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