SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89587ad5f948cc490ceb88deec8456bb8d2aebe1f1509121be2ed9deaae9cc35' 
  AND token = 'nglTZVmgGkskM5hBNoG/hvKuPRY8o03BsLrIXSe0gyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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