SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e45e482722bdf90b9b18c15c4c2f3fc9745077088be2e6dd9d24c1b50c3ef3d5' 
  AND token = 'LYBkBcDlZwwdf1LuDjswRlhusTFvcIdVzaLGbcG8dTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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