SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '763fdc35de2d5028728191424cce531992e416eab3ee0b9605935f50564ab668' 
  AND token = 'hbss9dECkrJj2V8v6plj9RItFOnf6uE1L3VgDount7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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