SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '441c87ed742f617cf756afa81e6fb64889e645accaefd637b6b9021fffa33756' 
  AND token = 'VYpqBeVa022efh2DIYmy4FwIjznt5+1B/U75lXwG0sI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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