SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'da65b99b13726b1fd8479ca3f3528e5c9733cdc50908ad1b687f4a40d251da3c' 
  AND token = '/lqCgIBuCFVYG0Bk4vZKSurv+fCuuJI9HBFaT6Mlobk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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