SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41ad786405e106c0726aba18282ee285eff23f7f1683168837c6307ac6e2db5b' 
  AND token = '5GC10EwesG2IV7ZqteEz/yicyr1IZxOw9iyMsgO+/rI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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