SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b974295a64a44120ede472da5047b071a9af0bfca8465bf0f83ca7ff898ca3d6' 
  AND token = 'PCWxw2Vr1tk13lOgbLv085tSOomRV8xaXQNLDXE2Jvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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