SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a33228bbde723e6dce216ca9d8da172d4a5c10b594d70bbd8716eae20e9a37dc' 
  AND token = 'sIefbrVCJCpZtspfbKn1V6Xb6bicDWN7pKVYNpwtGGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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