SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81d94b7666fef9b2e1771d5b50b5f9cadb80ca6796cbc29c53add361a596529b' 
  AND token = 'JFzvDOQt1g0UJzkLgRltOXJbiCPKzs6XTTmCzIZ07jU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}