SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47df35be1af3e0bf9f6bfa3e548d69a1d1041a37bf966ffdae257921872ac1b8' 
  AND token = 'hFfp4CQVSLSZXb+DpNsiZ5jRlSpTRB+JhGBobcC6mOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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