SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '477e96a2bb36aa52604f380053345bb2917b494fcf9ff9c22212872b24225321' 
  AND token = 'iHa2P0EOzK+qwguWxdZal/n9f6VaAmMX/p690ghBBTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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