SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d877dc887941727b3f9b098300e568ec8331a47a64457c522e9395d15bf7a77' 
  AND token = 'qVozfpxVuoZQJnH4MbN5gJ49841CoPVJ4a8ECZFuEhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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