SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c03c6e99ccba9472143d6790065beda095509e1fd168deda9c7c666e7f2da83f' 
  AND token = '2NB6Mvd2KHTAS23HqNJuYHZkNxwdyWkhiIuluc6ywG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}