SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec5fdfa71e7f157cee98dc8b4f7b213f42d9dd952ac040fa212105cad05aa529' 
  AND token = '3ggeNBTvGsKXhVgx+jTmcaeftsKr7+kCCdWzubGXcmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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