SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31e2a52576fb913020fe6a1655c42bd1c152af99ee573a075469dfb9920df7d2' 
  AND token = 'K6AsEXUuqXck1PV6oQnervH+5VqCycENaN6X39eKZyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

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