SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16933784c9270fbbdc83bc76635526e95b8b647b5a2274545f2e0ace4aee2184' 
  AND token = 'QcZYTXb1TQHZw7SEgugjDQT5X6AftHRocEM62+ATRfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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