SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8bd226033be6c51d2d8baefd45efe233bd353f409cd7d6dbae50097f185a5f3d' 
  AND token = 'cEgFv0rLgOKpxEBRDhovFM5u3rVqcbkAwXbgn3wzu9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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