SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6a53da9606483a60c84e836b67aa5c5840a4824dec35b6b99282895c6c1d07fc' 
  AND token = '+om0HUt0QjM5uQPIS0z1pez8unkCipqpMXODTt+OV8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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