SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f54678c222cbb781905de7e4fe19eba2cb5b542ec824d247645a5870f999ffca' 
  AND token = 'HrwSx5/2KcYnbBt80nMlduBvfB9CJVjz7aCjoh+0QII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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