SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4231933baf8acd37c86dc5a564fbc7972e2fe264ac687141b3bbd3056eb08505' 
  AND token = 'ev8/gPAdp0WvF0iwbtjuwsuaMfWqkAVyBiR5bS1mbJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00074

JSON explain

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