SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd90c9045af5551ad1c2e3a38c4440d4820d8b20ba571ccfb3086ae1ea6496aaf' 
  AND token = 'mUklw6yG2fJ5M8KjCjyFcLsv6jzumh2HF2jR1PXB5+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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