SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47c3dcb38bf637266d1e9d6f4456b148b02dea3e85f81521c4df080210264eb4' 
  AND token = 'XlB7P+NSjpuYGB73z8VGBjU8GW2Gf3qe8+z3MDkI/io=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

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