SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '050bb881505fa4770c4131b40df36071de6f63409939a36711532ce83a7aa600' 
  AND token = '5HwIf5QmmnS2BSqQDmwQaCM9ktFjdu5WYklaeiJktkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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