SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73d94717229a84822e790a533702670437acd546c4228ced5aa6c6b83e466ef6' 
  AND token = 'ZYmZlinldzGfrM2nksePc+PdRd9sHPFTltce4Un2jko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

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