SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b444e334bcda538753dddfde82752405308e023e7b93607eaad148f3f2b88b6c' 
  AND token = 'scBVC37RrlbMxUFo07qBWU56EnWTLANtCt/04AmCppw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

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