SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b4b1d58bb2ab9e57449cd162d5711c67382adb6e3a2a6eb5ac8b450f7c557e3' 
  AND token = 'TkLE5avriouVjFThfyml/6EXtBcceOx9CtlaKlfnbA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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