SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b5ff83c5d38f1660586886d2bf7d4099b0446ef810cd781b3d0c37dc8c08997' 
  AND token = 'sSTaVFllbnwtBh39uy0OSM/9ZtT5fzBGXGpVdTXF/QU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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