SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8d09af5a2637c62a0d79dd13cb6c287143c1f40225c1b999aed09a50b51fac4' 
  AND token = 'tIw4uxzuBkQcX01lZPShSQ85HaWYwKUWgyRPd/UG6CI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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