SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4a3b25cbef4ad48b8a9c5c35416b1dce5cb3cdc9dd6f3a96912849d480eed753' 
  AND token = 'KJ+SejIdiJOqcKJ+7vyiVCKpgAVXfhZadn6+zFpJs4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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