SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a85394408b4cb0df885e99ba9ed94b8f7db3cc5f9f4104fd286f0bfc5b820e69' 
  AND token = 'aGRoVubG3godRWVp3STF4nfDwmsCADEtBaDKxQEjUXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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