SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56935ff4790bdd62905e812ae960576d61ce31257348ff49ce9b4279094eed58' 
  AND token = '4PgpIPkLFAuIviPs5wWYgu3hfg4Q/MM7OjfN1YW8k8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

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