SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '749abe6c2501e8c0f6993705630ea89b960be0e9dfbe46af0c61b7de14397f9f' 
  AND token = 'HSYVT50+NxCp2HfMRSwjhyUsRlSZHxIuu+7/ccdGh54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables