SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88418490dd1cbed53ff7224474aaa4429816d51ce006708bc205788de39a3bfb' 
  AND token = 'G7NF+9jv1MxNiI3rtySA7BzqQIojODayuYxUoeHoH5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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