SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a63d39df7c1249cd0a887458df87994a39469f19955f834b15602dede298031' 
  AND token = 'JsEcw5y7qElohAI+zOlRbnFf27eB/sY0+1Ps5ZPjH/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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