SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '777d8d61b1fac60e1d656f9c7a1ad2b42cc3bcfa640688bb994c4ff63ba0644a' 
  AND token = 'po+NSpuIwNaTovVfRcutIDGpOP6/rEFkKUQp94+erMg=' 
  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