SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f575feabb7127ff658fcb48a6e7e466333537138fd2513324b66f24a3d1f2b81' 
  AND token = 'i+Sk9vZlln9dNQw7t89ssCfLOED33AxlJsrlYxKqiB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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