SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c28c8464c8fb7599637b4a578c012733b9daa252afba7f4472061905ec779e95' 
  AND token = 'sYmziRVWZ1NrIOM/wGFSRQRRVWGlhPXDgJBXLdaztII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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