SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c28a2b10bcfa7121d8cb88f22de88ecc20d59861b1bc4679711a0c699aa93a67' 
  AND token = 'UYkFarNHQQKFEGfMOYVM/YtFH7w3TxQt5WSo+cdUjJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

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