SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c2730971a23d263164dcf4205720145aac3b1d84489c60b42afad5d93aa3bef' 
  AND token = '1TEsMEw0N8XlMCVkUFBcAHdz5sLvvS7CADBH7unx85I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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