SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '719aaf3a9f244a8857227192334d0229a6b3d7fcb469fc1293c988f0044d035f' 
  AND token = '61ZlOkGMHxwg+UF0hte7dbB8kHgVMwHQKpgGpOvAn/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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