SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ec77bfb0ee74e843f1bcbf9f5c991c001cb240f2fae7220a620b77e808181d4' 
  AND token = '81wOM2zmqkvdMa/EJ526bUE354/Zy0OfYBTJbCwobik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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