SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68ee70c574824c631793566444dcb006bf105fa94f1b0ac4dbfa525d01723c97' 
  AND token = '+ARMkAaCr3kKIAMl4GfFa0DF2zx1LKgZ/G7njua6Fbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

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