SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '920e936c51baa090e07db1f66cc0331fe60c9b97bf65fb482ee27dc92c1d89c2' 
  AND token = 'duJipY1JC3CevJ4Go/LVu0Dnx+SKz7qFmWTVh2vvMzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}