SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acf94677aee1f941380be4f63da7523c62958d9f378a37712561f2220f518830' 
  AND token = 't9J+aWrIm/jY5SWhxFyRtWuvqHfwhE7nBuGwSjtsp+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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