SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '718b28ef0adfe163fc835766015df2db208731b063511875f526f4cc57c0a533' 
  AND token = 'OpFzkEkoeRQfhSEdcP8TTr+yIzl6wwWvAISCbKYBGP8=' 
  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