SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29db193b295f65c05617a868b655b7ea693eb1cbd8047563aa033af8ea5bd2ae' 
  AND token = 'UQK38aZCKMbPfHMgNhyiRQ3pav6L+hSQBvwVsTcHqzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

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