SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a27d9605566933993d0300d141c2ad5881b733045492a14e0e6e579166101036' 
  AND token = 'XglhtZ0UzsgNTet7mLttmvGGZiSwcTsYU5AfUFES5Ng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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