SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98e0bd6452a6cf91d9c81d1e20226898d46dea0e7892d5cea060a722adcf0a1e' 
  AND token = 'zojDNJsww/cLlcuivhHxlg9ypTv+AAEpknLNijaNRzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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