SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '506dad6b278557a15169a046be7eecbcdad822cf11a952d1cc60c95a8b01cdc0' 
  AND token = 'imDDSM+UOJK1QhyChsMO4qrPJdYaBocHfUiWeh+206w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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