SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f320847b6ad69ac86369217a2ff41cfa391f80fe240cb9efd34150f8273fdadf' 
  AND token = 'yt0XBTylkV1JQhHBV56Klrh4GRmdCzlkztWFeJtoAFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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