SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff0719881b106ae7391de8777c2fc2241113c031e78207b0c2cacec9791e1644' 
  AND token = 'PjcBmMT2RjJ0m2aNzY/2Yw3Eanz7SkU0u0/zTVyRBFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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