SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5493a91650afb1a10d995b13618420d22d89771de1bfe08557a0ace43d40a3ea' 
  AND token = '/8BIEPXDPpRt4lpAjD7zxvygPfp/rC50jZFdd+a5L5Q=' 
  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