SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '195b348e6548672466a0ef7d58c78406e811601351c2f8abdd573c632d0eb293' 
  AND token = '2ul4JaxHf6vTd08AEG8YTkfhNgQfoHTwyr5v/YEIuJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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