SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd3793d29fb4cacd8073aec1c492b71ec369ddefdcbb21ae23246ee635616538' 
  AND token = 'IXW9XgWKU7fCMd4p3SJuwVNxml+/5qoBJSZOpTIHvxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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