SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cec6d2efbbdf1ec106c7d31e891f240513ba11485f551f7acedc4ccbc65baf2e' 
  AND token = 'jr+pU+V1Y3QADZuKcjqcuC0umEJ99Km+s/IQDIoN+1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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