SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd8a50ed002dc784b4a1e758b31a5369237075f77009cc05c153a29c932b5072f' 
  AND token = 'fxOstHkkjulUi4YnYwNvj5/uwlHEmQHvxz52tVm5M4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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