SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '22539b91a0db564f37750d0d321a703af9531ececf5b08f930d6b6006c7d4cfa' 
  AND token = 'Rst0nP/LJ4ex6tKjwDo+exYKY2uwlGueINWcxiq3IBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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