SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e8953788e65580a4caf5b42421afc290da171e7afe826ec9dcdfd39831028ea' 
  AND token = 'fVskhMjXvgK28X7fg7uwlXxK6yGUp4JogFcQUSGvQtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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