SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12b85544f4c47a462af0e8e917ed578f8ec0785bccffcbdd0c61cc36f4e301f5' 
  AND token = 'AnbHapHCDrYoqY0ykqqcnKpBmEVhmWUYmxo4NGmPCLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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