SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '529210f3b638048914506fb11f721a13f667a17f39b9584d45c79cc0ad261bf2' 
  AND token = '69wBx+uvvAvzmEEFtsyqH7wEz2dOSoe+sNLkjG/Q5dI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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