SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3fd9e3ead902fe5a429fd8fa292dbb1da1acf3d843ceedabeddd578e7c4b97c' 
  AND token = 'Y/vOIcSQBB+5tFSm1s9a8YzFIlsC4NCHIqM/MmkW03I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

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