SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b35016d095667cd024be196eb044c1a002b885e8c1009f39e192629f9ab9c610' 
  AND token = 'MaJCguSMLdSDh0QvcxNxsfbA7LIw6RQIc2aFklvhE+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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