SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e808fd4587117c7d4f89751bf9817064fdb5ab60a64238ed6f530a32f719adb4' 
  AND token = 'AVC2fMqXil+7LRCCy1C0mUckRTzow5cgjdCJnetfSZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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