SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '289cfaa873307d19bb778a79180565121b66015f9cdcec935cc074c1366d0be7' 
  AND token = 'zvasAp6kopK3vh8WnHompIAyo04FkUsMQml6oNLAUmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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