SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e29e915e82bf9cf3746ab9d62b13f7694cc8d52f7f37abd90258f3bc05ac4d31' 
  AND token = 'Lh8hgPUZuj1hReWHrFH5MbTmnn0gUmjNRZ+ChtOCT8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

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