SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfef35a6122910be8ae56af5ddf920ec2aef6e3bc7d65934891894c8412a298f' 
  AND token = 'i7yn5pxq5WOiUbVYcTqwzsBrgx2aOZiYa9ADXuvQTiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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