SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f89b68857255d63a2638bcd5270e1849f243aac4aad78c344e4c905521020b34' 
  AND token = '/NqbkXu3QC4rJA31c122i3XhB2Dy1QL8bNJ1Nrt83eM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

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