SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8295a2c0374fe15983e44306570db7cc19e3c5c66e715681166f325da09c7438' 
  AND token = 'RXLLJd++IwupwY0az5+yhNnnh5PKamJgeHaKlt8+q70=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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