SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31d3696fb1062485300126e79fdc6dd9f232c5d298486523a5a057ea3c664152' 
  AND token = 'ZIauKhuJLBaADV1Rt+yXdwEU7E0O4NgrxYjoG91j9gI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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