SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92bff3dc6fe7cd15a86043fd53f07bf4ff70154a4a52cac4c5fd4e9df17e9690' 
  AND token = 'jLM+TlweK5cr3yO+A2N/YDWrvuieF6Txv+o4aJHh0nY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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