SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83b51f397165f1997893e2d0d0182cb5c16389ffab618fccffceaeb4d1e76b21' 
  AND token = '7y7yJP77Lvsxy8vvuTQyETvMuu+J2avWMzYz8AZimpQ=' 
  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"
    }
  }
}