SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b74c3f368f384c011dcaec4ce153f8df957b8ad2ccbd007865d06f09146fe481' 
  AND token = 'g8ETCnl1/dma3+Bvn8ytGCa5aSXZPKfmIr1HrEwvnQI=' 
  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