SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cde0be6f0b0574a7428b58023d50a3fc999199c525e5012c77e33bcf2a513e72' 
  AND token = 'hYGTHFZOzf81/1noBJXuWi8lmpzh8xPyiqjI3d2oIsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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