SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a99856390c5bb28910403ebe90e878147591232851dec69a9e4c7524735df61e' 
  AND token = 'qVbv8M74U9ce8nKZZHkHvL2/+SOjCH76TWMqXge+HP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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