SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98c8e17a3cf03487170cd50eed06fe70b5dedd80c780bccd2e912d794eadbeaa' 
  AND token = 'YBH+A7EnaQ1yl3ZKdEBll7boB1FP+qPsDpZcr+gWdEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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