SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '816841c2ce341e6bb2fa341fff2015728b43d05ea37a0176b594332670b7f020' 
  AND token = 'eLnmUMKw/Y2Y+7PJvybq5BYkjwoyvx9wQwR/nReQPQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

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