SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd406a85c3bd6da8013c4d880adb354c88dc6ae6a028b598b5dcc7b3af2367688' 
  AND token = 'DmAYNxmlBvZxtKIQWKkoN6knqUl6/LnzU8y6IDpeqH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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