SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a1e01b9bda72b3f68c8bcf73cccf8b61b7adc1190abfac127358567a58911ae' 
  AND token = 'ZRa1YXyszDEr4JC9ntVEOk5iCXuKQaCtPVNqPrMuIeg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}