SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9c69f7bbb9383dcc1a344a646e25e348f1c53faf54124fc91f82fd986a258f2' 
  AND token = 'jg0h0HYUg2KoaY3vrWVzgx6LgXWF8m8ABPwc9pkQ2WU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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