SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb2a10aea075930a2ca5bb05dcb12dc0faa3b7d4105913654c50bc73c751344f' 
  AND token = 'AUULDnrfLMeABHTyeCsxD7zT+55v5z4vsDGb1ZQoUtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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