SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd4dfb78a825b6ec3db04b2ff9c30eb8fcad252b50c464fd27e1dfeae1e98697' 
  AND token = 'KMihpBA/HtGOpc7fjw+tR+lz3nfYSP8SuK7k7CMY0ws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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