SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecc70fd4f2d464221818a2d45ce12b9f43aca4abd22abda5413b2e9815fca35f' 
  AND token = 'prLZaf9TdeWpUdnzdPviphpXzUYZ7DM+N4g4SMAoUjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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