SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c47ed9e6e5eaa426e967045bad344ae1f6a1353a9955f618a78735581296d9e7' 
  AND token = 'gvAHho7aoygFg6jF40krBSR7rplWz3mycNZ5+VRAEgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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