SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9eb18747a806ce1c538ad76d3dfd18e298088b39fb4fee3ad57907b94f31d34' 
  AND token = 'QX5KgfOzf2omTgmYhvGeyWpDohYaBxc/pkSz6aufgRI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

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