SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '391eef4d3196745c08436e8772466eff40e878994e8d52c1d7e1edbdf3ce0d6d' 
  AND token = 'tCqBZ7u/U0rhvOEwhoglD+raF8soruC59Hmcy4O1Ojw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

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