SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd171335ba1d7d21984f981776a7821043a4dcd38c6fb3090234bdf4516e19978' 
  AND token = 'IxFx2lbpxCn3KMHG/3TVScSc9mb2/i2hWiGBJbKgjY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00073

JSON explain

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