SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '284b3bb2df9f85724f6dfd454e80b70f974b7b5afa9536853bf7f1d16fb8418c' 
  AND token = 'ObhyYi1nCJmRp/Ok/lr+Szg3ZD7YJ/lbU0MALgot6Cs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

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