SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e63e4fd9b2f007abc8ed957f162ce3f81cd2aeccfe8676ce83b6470a89a99b0' 
  AND token = '08Jk9N/IQdD1Tk/XVUfyimDZOKjK4BTCU1iBIMhKTmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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