Very slow recording after adding Trigger in MYSQL Insertion

Question

When I insert this Rigger into my database it is taking a slow time, getting to give this message:

Errormessage: Lock Wait timeout exceeded; Try restarting transaction

My Trigger is as below, the cod_prod field of the products table is indexed correctly.

DELIMITER //

CREATE TRIGGER ESTOQUEENTRADA 
BEFORE INSERT

  ON estoque FOR EACH ROW

BEGIN

  UPDATE produtos SET quant_estoque = quant_estoque + NEW.quant_prod WHERE cod_prod = NEW.cod_prod;

END;//

DELIMITER;