SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c6430b2b71f4552827795507ad1e5918b32d7782285f304fb99b6ec44b848ab' 
  AND token = 'PifA64Us3G41yTLvzHIuTg9j+HXWWuPN/gatbeaSIGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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