SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75c1f7e4b248b920fe2d8a07c25fb2fabcce372175372191bdd7c14ece2149d2' 
  AND token = '+9KOg8xnXyHXuLtX8F1EfL5+ZgQFlzTRYP4oXPTMroY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

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