SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4fdfa494206f6be0d910993fff890ed52bd34176666b76044c2aa872013d33fe' 
  AND token = 'TXwnS4br8ODs0L24yGLhDbnEKCtqeaE3tGA3gP3dTv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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