SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c4055e8987058da24e3c519844c67edc2c42d9bf25e03945b7d1e92b9eb1f8a' 
  AND token = 'clZ8bhQmi5SW1YAzpRJOW9WAo52oESIYjo/ek4wVcIE=' 
  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