SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2b43133dc78e5f9024d4214c2fb276594166ec42857fb84f4c54bf145f88551d' 
  AND token = 'wrWllq+OHBhMeME583Q+OPSNWHkHvY9/ltEitIxOTkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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