SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eab7786b502aa55f202fe6aef73f9648841fd952b770c01293e4865f6a7ebb0b' 
  AND token = 'tQsyk4Lo2YHu+aLdevQr7UcZ8nphLU1IHaXEXgdWpyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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