Rewrite to new URL and 301 the old page to the new URL
You need to rename your products.php to products-new.php and create two rules like these:
RewriteRule ^europe-cell-phone/$ products-new.php [L]
RewriteRule ^products.php$ products-new.php [R=301,L]
You need to test the original request in THE_REQUEST as REQUEST_URI already might have been changed by a rule:
RewriteCond %{THE_REQUEST} ^[A-Z]+\ /products\.php
RewriteRule ^products\.php$ /europe-cell-phone/ [R=301,L]
RewriteRule ^europe-cell-phone/$ products.php [L]