SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afcbb616b9388d5b0e127ee911fe1de3fda5435fb3b528c4d5303381c86da9a8' 
  AND token = 'ScbnJHUjIudyxb7nb6ws8GbcwPOVtjHz3WNUMyn+uWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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