SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '695007fbc510783bf13f299cd608398608eb7b968c95a52250ff834c5648c0ec' 
  AND token = '9zG0XHQwN7rtWLYjVciPgj+y7zoJsOWb4vPZrOfBZVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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