SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '423992db541f839e418276471e365c71d3eeeecb6f16766247ac9f7e63e7718f' 
  AND token = 'xQfmJe2llK5+/G+WLmuNhVEGHBK/haGgCje4NrYoKuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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