SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8742bbf5a38e9d481f6c78cf7d5795cb8e85008ea34b5c037606b7d06d0e6d7' 
  AND token = '7HTBXFMSr2a5N4Nq4sKSkAbw/iP9DP8lvg0lftzdwxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

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