SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '238b5e73bf1a420b5870119a8161ddb179585a513ec997c9c08bbaa09104ddcb' 
  AND token = '6x2cUKUSZSgqX8xZLDMuYZwmOhS5unsE+6yqwtz13m4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

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