SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1600f33b90d5adb14679fae2409bdf324205135bd4755d37b30a5b799bbceda' 
  AND token = 'SKFWGufFUwYcmaCor7vYtk5rjXPh3EurRCDfxj+Yoek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}