SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b84c8191a8c65670bfdf035eb45d174726ea2f21f49cb3d2d2a9b01e28350cb' 
  AND token = 'jas/tiEAtIFM5vn/EFv2sVff4l1WuTlztRtYoZ9nbpw=' 
  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"
    }
  }
}