SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b40b526c40bb4467a0986df32841180762640377e5a7fb1c86820c6f326010a3' 
  AND token = 'SAM5tC7wqj/Q0F1P98cV1CfxnOD+2E0s+tg9/bCfTws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

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