SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e5ae77feb4b313a288b9b669c08fbb08f49d31062fead634dbe8afb6471763c' 
  AND token = 'HX6lBtIfebRWZdcxHzV3iHiNDEMk2hqBsRRb0g50ddI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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