SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31744641655a6cc47408523bfdfbc543a2dbbc73f4c7e807ef4778b9ee64a395' 
  AND token = 'rnl/AdYfbbgFkzBx5gNf4kf5BvFAHmpYG1d50ZBcbyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

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