SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efbc620b50662a7320fc5d911008c7c1526d7bded1a788bd49aa7cd4575ab626' 
  AND token = 'GLjQdK4MuJpsRDUvkYpLdXmeDHH21vXuea/SUOkUahA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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