SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2504e74fc51d3e189c89ac17ab4220548753b62bb9baeca827a132d452202691' 
  AND token = 'lvZz5uL8PsUndD9DVHSgstQQY+hR/ySvlsFryrnJCx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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