SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a982d3b74115b8da738759b6fc224e72eac134cd69f2be0daef4ef0733582f95' 
  AND token = 'ei4FgMtuso5Czjht2nWpGG2Krh4DHxyZGc8s47/IPOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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