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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a98b19675084d5fc4fa9a3008730e13cf1566ee376f8683cf56f82da7cd4c5bc' 
  AND token = 's5xlGv0ezEVSgar0UEqqvSp/NLeFA0DQRPbpb9WS+JI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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